System to charge my Tesla

Spud

New Member
Joined
May 18, 2022
Messages
1
Total newbie to solar but very interested. Currently charge my Tesla at home on the grid. Is it reasonable to set up a solar system just to charge my Tesla? How do I figure out system size? I use about 900 kWh/ month, live in New England and have good solar exposure.
 

BentleyJ

Solar Addict
Joined
Jan 13, 2022
Messages
715
Location
Riverside County, CA
900kWh per month is 30kWh per day, generally speaking a 6kW solar array would be sufficient. To more precise you should go to https://sam.nrel.gov/ and use the solar calculator for your location and roof direction to determine the capacity of the solar array needed and then compare to the actual roof square footage you have available minus plumbing vents Etc.

You didn't mention if you want to charge the Tesla during the day when the sun is out or store the entire required charge in batteries for use at night. This consideration would have a major impact on price.

Overall based on limited info provided, it does seem reasonable to set up solar for charging your Tesla. Batteries are the deciding factor in my opinion.
 

SAJ

New Member
Joined
May 16, 2022
Messages
2
900kWh per month is 30kWh per day, generally speaking a 6kW solar array would be sufficient. To more precise you should go to https://sam.nrel.gov/ and use the solar calculator for your location and roof direction to determine the capacity of the solar array needed and then compare to the actual roof square footage you have available minus plumbing vents Etc.

You didn't mention if you want to charge the Tesla during the day when the sun is out or store the entire required charge in batteries for use at night. This consideration would have a major impact on price.

Overall based on limited info provided, it does seem reasonable to set up solar for charging your Tesla. Batteries are the deciding factor in my opinion.
I would be charging the car at night so would need batteries and an inverter
 

BentleyJ

Solar Addict
Joined
Jan 13, 2022
Messages
715
Location
Riverside County, CA
I would be charging the car at night so would need batteries and an inverter
To get 30kWh of useable power, battery storage would have to be 40kWh of batteries after factoring in eff. losses and 80% depth of discharge limitations.

For example EG4 rack batteries are $1,500 ea for 5.1kWh. You would need 8 of them, $12,000 and that doesn't include shipping or the racks to mount all of them. We previously estimated a 6kW solar array and an 8000+ Watt inverter(s) that will charge the Tesla in a reasonable amount of time is going to be another $12,000 plus or minus for materials. Installation, is it DIY or professional installers? Many jurisdictions will only issue solar permits to licensed installers. Bottom line: if you like the idea of being energy independent with regard to charging your Tesla and $30,000 is a comfortable budget number then you could indeed charge your Tesla from solar.
 

Supervstech

Administrator
Staff member
Moderator
Joined
Sep 21, 2019
Messages
7,741
Location
Belmont, NC
I would be charging the car at night so would need batteries and an inverter
What average range do you plan on using daily?

If you push the range of the car, no… it’ll cost $30-50K
If you rarely exceed 40 miles a day, sure, not a huge deal…
 

SAJ

New Member
Joined
May 16, 2022
Messages
2
To get 30kWh of useable power, battery storage would have to be 40kWh of batteries after factoring in eff. losses and 80% depth of discharge limitations.

For example EG4 rack batteries are $1,500 ea for 5.1kWh. You would need 8 of them, $12,000 and that doesn't include shipping or the racks to mount all of them. We previously estimated a 6kW solar array and an 8000+ Watt inverter(s) that will charge the Tesla in a reasonable amount of time is going to be another $12,000 plus or minus for materials. Installation, is it DIY or professional installers? Many jurisdictions will only issue solar permits to licensed installers. Bottom line: if you like the idea of being energy independent with regard to charging your Tesla and $30,000 is a comfortable budget number then you could indeed charge your Tesla from solar.
Thanks so much for taking the time to answer. Using your numbers it doesn’t make sense To proceed. Again, I appreciate your help.
 

A.Justice

Swears he didn't start that fire.
Joined
Sep 12, 2020
Messages
1,293
Location
TN
In my mind there are two classes of "personal use" solar.

One is a "toy" or "backup" system, which, IMHO is a system used to run essentials during a power outage, or an RV, tiny home, or shed. Usually single phase, stand-alone, and most of the time doesn't need to meet code. You can normally design one of these systems yourself for a few thousand dollars. A lot of the time (depending on where you live) islanded systems aren't required to meet code, or be installed by a professional, as long as they aren't capable of feeding into the grid in any way. (Don't quote me on that, I'm sure there's other states with ridiculous codes, but here, unless it's attached to the grid, there's no permitting or inspections required).

The other "class" is a system designed to run your HVAC, pool pumps, EV charging, etc. The amount of power produced by those systems almost always requires electrical inspections, code compliance, permits, and professional installation. Even if you have the knowledge to do it yourself, it's generally a serious financial undertaking.
 
Top